Where do the spark plug and wires go on my 1999 nissan maxima

The Spark Plugs are located under the Coil Pack in the Cylinder Head. You need to remove the silver cover on the front part of the engine which are held down by Allen Bolts to access the Coil Pack. You will need to remove the two bolts holding the Coil Pack to the Cylinder Head. Pull up on the Coil to remove the Coil and inside the hole will be the Spark Plug. The rear part of the engine next to the firewall has no cover so you will need to just remove the Coil Pack. The Nissan Maxima is very picky about the brand of Spark Plugs you replace them with, You should only use NGK Platinum Plugs or Better in your Maxima, Any other brand will make your car run rough.